Elevating-chair



(No Model.) 2 sheetssheen 1.

W. B. MANN. BLBVATING CHAIR.

No. 547,221NV Patented 001;. 1, 1895.

f my In AT1-naman' ANREW RGRMMM.PHQTULMIQWASHINGTUKRC WITNEESEE (N0 Model.)

Sheets- Sheet 2. W. B. MANN.V

ELBVATING CHAIR.

No. 547,221l

Patented oct. 1, 1895.'

ANDREW s GRAHAM. Pnommno WASHINGTUNJHI.

@Nima rains WILLIAM B. MANN, OF BALTIMORE, MARYLAND.

LEVATING-CHAIR.

SPECIFICATION forming part of Letters Patent No. 547,221, dated October 1,V 1895. Application filed May 19, 1894. Serial No. 511,761. (No model.)

To all whom t may concern:

Be it known that I, WILLIAM B. MANN, a citizen of the United States, residing at Baltimore, in the State of Maryland, have inventedcertain new and useful Improvements in Elevating-Chairs, of which the following is a specification.

This invention relates to improvements in chairs, such as are used by dentists. In chairs where iluid pressure is employed to elevate the chair-body the latter has been lowered by allowing the fluid pressure to exhaust.,

My present invention has for its object to provide means whereby the chair-body may be lowered against the lifting force of said fluid-pressure.

In order to make the improvements more clearly understood I have shown in the accompanying drawings certain means for carrying the same into practical effect without, however, intending to limit my invention to the particular construction which for the sake of illustration I have set forth.

In the accompanying drawings, illustrating the invention, Figure l is avertical section of the base or pedestal of a chair embodying my invention. Fig. 2 is a cross-section of the plunger which slides in the cylinder. Fig. 3 is a plan View of the frame which carries the chair-seat and rotates on the head. Fig. L is a top View of the head which is mounted on the plunger. Fig. 5 is a horizontal section on the line 5 5 of Fig. l. Fig. 6 is a horizontal section on line 6 6 with annular riln removed. Fig. 7 is a detail view of a portion of the annular rim of the base, showing the lever-locking notch therein.

In the accompanying drawings, A designates the base, which exteriorly is cylindric and is supported on feet or on an annular rim b. It has a bottom platee, which serves as the bottom of an oil-reservoir B, and a horizontal plate d above said bottom which servesas the bottom of a pressure-chamber C. A top plate c serves as a cover and makes thepressure-chamber air-tight. Two small cylinders D E are in the present instance in the base A. These may be formed or constructed in any desired manner. In the present instance they are formed with and as part of the casting of the base A. The cylinder D is for the plunger F, which supports the chair-seat, and

the other cylinder E is for the pump-piston G. 'Ihe pressure-chamber C in the present instance is designed to hold both air and oil under pressure. It is obvious, however, that instead of one chamber to contain both oil and air two separate chambers may be used, (one for the oil and the other for the air,) and a suitable communication between them, so that the compressed air may act on the oil and impel it. A pendent pipe F is on the lower side of the horizontal plate d and the bottom of the pump-cylinder and projects down into the oil-reservoir B, and its lower end is open. A check-valvef is at the upper part of the pendent pipe to allow the oil to pass into the pump-cylinder, and closes communication in the direction from the pumpn cylinder E to the oil-reservoir. By means of the pendent pipefthe oil will be supplied to the pump-cylinder no matter what amount of oil may be in the reservoir B. I/Vhen the pump-piston Gis raised, it sucks the oil up through the pipe f, and the check-valve f opens to let the oil through and then closes to retain the oil. A passage g communicates from the bottom of the pump-cylinder E to the bottom of the pressure-chamber C, and a check-valve g in this passage opens to allow oil to pass into the pressure-chamber, but closes to prevent the return of oil therefrom. A chamber or passage h for oil to pass from the pressurechamber C to the plunger-cylinder D is formedV below the horizontal plate d by an inclosing-wall h. This small chamber h is thus separated from the oil-reservoir B. A valve "J in the bottom of the pressurechamber is opened by being raised, and has a long stem t', which in the present instance passes down through the small chamber or passage 7i and through a packing or stuffing box i2 in the bottom c. The lower end of the stem i projects below the bottom. A footlever H bears against the projecting end of the valve-stem i', and thereby said valve may be opened to allow the oil under pressure in the chamber C to pass to the plunger-cylinder D and raise the plunger F and chairbody. A check-valve j is located in the bottom ot' the plunger-cylinder D and has a stem j', which passes down through a packing ,7'2 and projects below the bottom. A foot-lever Q (shown in Figs. l and 7) bears against the projecting end of the stem j and serves as the means whereby the valve may be opened TOO Fig. 7,) and said hole hasa step or shoulder z.

The lever thus may be depressed to unseat valve and then moved laterally to a slight extent and thereby caught under the said step or shoulder e, which retainsthe lever and thus holds the valve j open.

The plunger F has at its lower end a packing 7.a to fit tight in the cylinder D, and is also 1 provided with a vertical groove Z. A pin or screw Z (see Fig. 2) enters the side of the cyl'- inder D and projects into this groove. The E plunger is thus free to raise and lower but is hindered from rotating in the cylinderby the pin Z. It will be seen the lever His to cause the plunger and chair-body to be raised by l admitting `oil under pressure to the plungerl cylinder, and the lever Q is to 'cause the plunger and chair-body to be lowered by releasing the oil from the plunger-cylinder back into the chamber h, when the plunger is 1 forced down against the lifting-pressure ofthe i oil, as described hereinafter. vers in the present instance are foot-levers but they may be arranged to be operated otherwise than by the foot.

The means by use of kwhich the plunger F These two leand chair-body may be lowered against the lifting force of the oil and the oil returned to the pressure-chamber C is Yclearly shown ini Figs. l and 6.

The plunger F is provided with ratchet-teeth fw to make ya rack. A d'ei pressing-lever l", pivoted by a `screw a; at the y side of the base, and a spring y, secured to the vertical side of the base, bears against the l leverI and raises it. As shown in Fig. l, this leverP is 'at its middle position. The spring y will raise it higher than shown in this figure, and when the operators foot is on the lever it will be depressed until it vassumes an almost vertical position alongside lof the base.

This lever has a stud or arm,

and a pawl w is pivoted on the said stud-or arm. This pawl engages the teeth w on the plunger. A spring rc2, carried on vthe lever, presses the pawl, so as to keep it in contact with the teeth w.

The pump-piston G yis depressed or forced down by the lever J, which is arranged vt0 give great power, and said piston is raised by the retracting-sprin'gn. A'suitable pivot-pin o is fixed horizontally at one side of the base. In this instance it is screwed thereto. The lever .l has its eye p mounted on this pivotpin. This lever extends alongsideof and past the base to the opposite side. A slot q is in the side of the pump-cylinde-r E, and a short arm gis attached to the lever-'eye pand projects through the vsaidslot `q into the cylinder, and a link-bar rconnects between the pumppiston Gand the said shortarm q. This short arm q on the lever is the direct means-which forces the pump-piston Gdown. Theliftingy spring n has its lower end attached to a pin n between two ears on the short arm q', and its upper end attached to a cross-pin n2, which rests in notches at the top of the cylinder E. The spring n keeps the pump-piston G normally raised. When the piston is being raised, it sucks the oil up through the pendent pipefand check-valvef into the cylinder E. Vtfhen the piston G is forced down by the lever J, thecheck-valvef closes, and the oil in the cylinder' E is forced through the passage g and check-valve g into the pressure-chamber C, and the air therein is compressed. The chair-seat frame N rests upon the plu-nger F.

The operation of the device thus described is as follows: At the outset the chamber Gis full of air (atmosphere) in normal condition, (no pressure.) Now by working the pumplever J oil will be pumped from the reservoir and transferred to the chamber C. As the oil fills into the chamber, of course the air in the chamber will become compressed. This ccmpression by the pump may be continued until the pressure stored up in the chamber C amounts to, say, one hundred pounds or more per square inch. This stored-up air-pressure is then ready to be utilized as the power to impel the oil and raise the plunger F and the chair-body. When it is desired to elevate 'the chair-seat frame, the foot-lever il is depressed by the operator, and thereby the valve t will be opened and the oil will flow through the passa-ge 7i and check-valvej and will lift the plunger F and chair-body. Thus the lifting of the chair-body at the incluent it is needed requires no exerticnron the part of the operator. The li'ftingis automatic. When it is desired to lower the chair-seat frame,the lever Q is forced down and engaged with the shoulder e to hold the valvej open, and then the lever I is depressed to cause the pawl w to force the plunger F down against the lifting force of the oil. The oilin the plungercylinder D will pass out through the open valve j tothe chamber or passage hand cause a pressure in said passage, which pressure when in excess of that in the chamber C will lift the valve i, and the oil will then pass back into the chamber C. By repeated depressions of the lever Pall the oil below the plunger F may be forced back into the chamber C. Provision is made to automatically seal the pressure-chamber when the oil contained therein has been nearly exhausted by raising the plu-nger F. This sealing will prevent either the entire exhaustion of the oil or the escape .of the compressed air. The means employed for sealing consists of a ring-dam or yupwardly-'projecting tube s on the bottom d of the pressure-chamber. This dam or tube may Vrise from the botto-m d to any desired height and surround the port or opening of the valve i, through which the oil passes to the plungercylinder D. A ball-valve s seats on the top of the ring-dam or tube s and closes it. A cage tis mounted on the said ring-dam and incloses the ball-valve and keeps it in position where it will always seat when the oil has been reduced low enough. In operation the ball-valve s will iioat when the oil is not low and will thus remain unseated, and the ring-dam or tube s will be open; but when the oil is low enough to allow the ball-valve to be seated no more oil can berdischarged through the valve c'.

The plunger F is prevented from rotating by the groove Zand pin Z', as already described; but I have made provision for turning the chair-body in a horizontal plane on the axis of the plunger, so as to permit the chair-body to be adjusted to suit the convenience of the operator. This provision is shown in Figs. 1, 3, and 4:, and comprises a circular head L, iiXed rigidly on the top of the plunger F. This head has notches u around its rim. rIhe upper end of the plunger projects above the circular head L, and said end forms a pivot fu. A chair-seat frame N is loosely pivoted on the end fu, so as to revolve thereon, and is secured thereon by a screw v. This seat-frame has two trunnions 1:2, on which thechairbody (not shown) is pivoted, so as `to permit the chair-body to tilt. The seat-frame N carries a pivoted dog u', which may engage any one of the notches u on the head L. It will be seen that the dog u may be tilted to disengage from a notch, and then the chair-seat frame N may be turned in a horizontal plane on the pivot c to any desired position, whereupon the dog will engage another notch and thus hold the chairbody from rotation. Oil is supplied to the reservoir B at the hole b', which may be closed by a pin or otherwise.

I do not herein claim means whereby air under compression is employed to automatically raise the chair-body without exertion on the part of the operator nor the construction of pump and float-valve s' shown, as these features constitute the subject-matter of and are claimed in my application for patent, tiled September 29, 1894, Serial No. 524,473.

Having thus described myinvention, what Iclaim as new, and desire to secure by Letters 1. In a chair, the combination of a chairbase having a pressure-chamber; a pump to produce pressure; a cylinder inclosed in the chair-base and having its lower end in communication with the said pressure-chamber; a plunger in said cylinder and supporting the chair-body; a valve to control the ow of fluid pressure from the pressure-chamber to the said plunger-cylinder, whereby on opening the valve the fluid-pressure will raise` the chairbody automatically; and means whereby the chair-body may be lowered against the lifting force of said fluid pressure.

2. In a chair, the combination of a chairbase having a pressure-chamber; a pump to produce pressure; a cylinder inclosed in the Chair-base and having its lower end in com Inunication with the said pressurechamber; a plunger in said cylinder and supporting the chair-body; a valve to control the ow oftluid pressure from the pressure-chamber to the said plunger-cylinder, whereby on opening the valve the tluidpressure will raise the chair-body automatically; and a depressing lever by which the chair-body may be lowered and the fluid pressure under the plunger re y chair-body automatically; ratchet teeth on the said plunger; a pawl engaging the said ratchet teeth; and a depressing lever actuating the pawl.

4. In a chair, the combination of a chair base having a pressure-chamber5 an oil-resn ervoir in the chairbase; a pump to produce pressure g a cylinder inclosed in the chair-base and having its lower end in communication with the said pressure-chamber; a plunger in said cylinder and supporting the chair-body; a valve to control the low of oil from the pressure-chamber to the plunger-cylinder; and means whereby the chair-body may be lowered against the lifting force of the said oil pressure and the latter returned to the pressure-chamber.

5. In a chair, the combination ot a chairbase having a pressurechamber; a pump to produce pressure; a cylinder inclosed in the chain-base and having its lower end in communication with the said pressure-chamber; a plunger in said cylinder and supporting the chair-body; a valve to control the flow ot' fluid pressure from the pressure-chamber to the said plungercylinder, whereby on opening the valve the iiuid pressure will raise the chair-bod y automatically; a checlftvalve,j, in the bottom of said cylinder; a lever to open the checkf-valve; and means whereby the chairfbody may be lowered against the lifting force of the oil pressure.

6. In a chair, the combination of a chairbase having a plunger to support and elevate the chairbody; means by which iuid pressnre acting on the plunger will elevate the chair-body; and means independent of said elevating means whereby the chairbody may be lowered by overcoming the lifting force ol. said fluid-pressure.

In testimony whereof I affix my signature in the presence of two witnesses.

WILLIAM B. MANN. Witnesses:

CHARLns B. MANN, Jr., C. CALvnnfr HINEs.

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